Systematic Review and Meta-analysis of the Additional Benefit of Pharmacological Thromboprophylaxis for Endovenous Varicose Vein Interventions

OBJECTIVE

The primary objective of this systematic review and meta-analysis was to elucidate the rate of venous thromboembolism (VTE) after endovenous interventions for varicose veins in the presence of pharmacological and mechanical thromboprophylaxis versus mechanical thromboprophylaxis alone.

BACKGROUND

The VTE rate after endovenous procedures for varicose veins is higher than other day-case procedures and could be reduced with pharmacological thromboprophylaxis.

METHODS

The review followed Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines with a registered protocol (PROSPERO: CRD42021274963). Studies of endovenous intervention for superficial venous incompetence reporting the predefined outcomes with at least 30 patients were eligible. Data were pooled with a fixed effects model.

RESULTS

There were 221 trials included in the review (47 randomized trial arms, 105 prospective cohort studies, and 69 retrospective studies). In randomized trial arms, the rate of deep venous thrombosis with additional pharmacological thromboprophylaxis was 0.52% (95% CI, 0.23%-1.19%) (9 studies, 1095 patients, 2 events) versus 2.26% (95% CI, 1.81%-2.82%) (38 studies, 6951 patients, 69 events) with mechanical thromboprophylaxis alone. The rate of pulmonary embolism in randomized trial arms with additional pharmacological thromboprophylaxis was 0.45% (95% CI, 0.09-2.35) (5 studies, 460 participants, 1 event) versus 0.23% (95% CI, 0.1%-0.52%) (28 studies, 4834 participants, 3 events) for mechanical measures alone. The rate of EHIT grade III to IV was 0.35% (95% CI, 0.09-1.40) versus 0.88% (95% CI, 0.28%-2.70%). There was 1 VTE-related mortality and 1 instance of major bleeding, with low rates of minor bleeding.

CONCLUSIONS

There is a significant reduction in the rate of DVT with additional pharmacological thromboprophylaxis and routine prescription of anticoagulation after endovenous varicose vein intervention should be considered. VTE risk for individual study participants is heterogeneous and risk stratification in future randomized interventional studies is critical to establish the clinical effectiveness and safety of additional pharmacological thromboprophylaxis.

Downregulation of ABCB1 gene in patients with total hip or knee arthroplasty influences pharmacokinetics of rivaroxaban: a population pharmacokinetic-pharmacodynamic study

PURPOSE

Rivaroxaban is a substrate for ABCB1 transporter and is commonly used in patients undergoing hip or knee replacement surgery for thromboprophylaxis. The objective of this study was to develop a population pharmacokinetic-pharmacodynamic (PK-PD) model to investigate the influence of ABCB1 gene expression and polymorphism on rivaroxaban exposure and anticoagulation effects.

METHODS

Five blood samples per patient were collected during 5 days after the surgery for the determination of rivaroxaban concentration in plasma and for determination of prothrombin time and partial thromboplastin time. Non-linear mixed effects model was used for a population PK-PD analysis and for testing covariate effects.

RESULTS

A one-compartment PK model with first-order absorption adequately described the pharmacokinetic data. The typical oral clearance (CL/F) was 6.12 L/h (relative standard error, 15.8%) and was associated with ABCB1 expression. Compared to base line before the surgery, a significant ABCB1 downregulation was observed 5 days after the surgery (p < 0.001). Prothrombin time and partial thromboplastin time were both linearly associated to the logarithm of the rivaroxaban plasma concentration.

CONCLUSIONS

We confirmed that variable rivaroxaban CL/F is associated with ABCB1 expression, which is in accordance with previous studies on P-glycoprotein involvement in rivaroxaban PK. Furthermore, we observed the downregulation of ABCB1 expression after the surgery. The cause remains unclear and further research is needed to explain the underlying mechanisms.

Non-bleeding Adverse Events with the Use of Direct Oral Anticoagulants: A Sequence Symmetry Analysis

Introduction

Postmarketing pharmacovigilance reports have raised concerns about non-bleeding adverse events associated with direct oral anticoagulants (DOACs), but only limited results are available from large claims databases.

Objective

The aim of this study was to assess the potential association between DOAC initiation and the onset of four types of non-bleeding adverse events by sequence symmetry analysis (SSA).

Methods

SSA was performed using nationwide data from the French National Healthcare databases (Régime Général, 50 million beneficiaries) to assess a cohort of 386,081 DOAC new users for the first occurrence of four types of non-bleeding outcomes: renal, hepatic, skin outcomes identified by using hospitalization discharge diagnoses, and gastrointestinal outcomes by using medication reimbursement. Asymmetry in the distribution of each investigated outcome occurring before and after initiation of DOAC therapy was used to test the association between DOAC therapy and these outcomes. SSA inherently controls for time-constant confounders, and adjusted sequence ratios were computed after correcting for temporal trends. Negative (glaucoma) and positive (bleeding, depressive disorders) control outcomes were used and analyses were replicated on a cohort of 310,195 patients initiating a vitamin K antagonist (VKA).

Results

This study demonstrated the expected positive association between either DOAC or VKA therapy and hospitalised bleeding and initiation of antidepressant therapy, while no association was observed between either DOAC or VKA therapy and initiation of antiglaucoma medications. For DOAC therapy, signals were the associations with hepatic outcomes, including acute liver injury [for the 3-month time window, aSR₃ = 2.71, 95% confidence interval (CI) 1.79–4.52]; gastrointestinal outcomes, including initiation of drugs for constipation and antiemetic drugs (aSR₃ = 1.31, 95% CI 1.27–1.36; and 1.17, 95% CI 1.12–1.22, respectively); and kidney diseases (aSR₃ = 1.33, 95% CI 1.29–1.37).

Conclusion

Results of this nationwide study suggest that DOACs are associated with rare but severe liver injury and more frequent gastrointestinal disorders. A low risk of kidney injury with DOAC therapy can also not be excluded.

Electronic supplementary material

The online version of this article (10.1007/s40264-018-0668-9) contains supplementary material, which is available to authorized users.

Rivaroxaban versus enoxaparin for the prevention of venous thromboembolism after total knee arthroplasty: A meta-analysis

OBJECTIVE

This article analyzed the clinical efficacy and tolerability of rivaroxaban and enoxaparin in patients undergoing total knee arthroplasty (TKA) surgery.

METHODS

Five randomized, controlled clinical trials on rivaroxaban versus enoxaparin in patients who underwent TKA were identified and included in this meta-analysis.

RESULTS

The meta-analysis indicated that rivaroxaban prophylaxis was associated with lower rates of symptomatic venous thromboembolism (VTE) (relative risk[RR]:0.55; 95% confidence interval [CI]: 0.35-0.86; P = .009), symptomatic deep vein thrombosis (DVT) (RR 0.44, 95% CI 0.25-0.80, P = .007), asymptomatic DVT (RR: 0.57; 95% CI: 0.37-0.89; P = .01), distal DVT (RR: 0.62; 95% CI: 0.45-0.85; P = .003) and proximal DVT (RR: 0.42; 95% CI: 0.24-0.75; P = .004). Compared with the enoxaparin group, the incidence of symptomatic pulmonary embolism (PE) (RR: 0.48; 95% CI: 0.19-1.24; P = .13) in the rivaroxaban group was not significantly different. A nonsignificant trend towards all-cause death (RR: 0.38; 95% CI: 0.03-4.92; P = .46) or major bleeding (RR: 1.59; 95% CI: 0.77-3.27; P = .21) risk between rivaroxaban and enoxaparin prophylaxis was found.

CONCLUSION

Compared with the enoxaparin group, the group using rivaroxaban after TKA had a significantly lower rate of symptomatic VTE, symptomatic DVT, asymptomatic DVT, distal DVT, and proximal DVT. Our study shows that rivaroxaban after TKA is more effective than enoxaparin and did not increase major bleeding or all-cause mortality.

Rivaroxaban: a review of its use in acute coronary syndromes

Rivaroxaban (Xarelto(®)) is an orally administered highly selective direct inhibitor of factor Xa that has been approved in many countries to reduce the risk of stroke in patients with atrial fibrillation and for the treatment and prevention of venous thromboembolism. More recently, rivaroxaban at a low dosage of 2.5 mg twice daily, co-administered with aspirin alone or aspirin plus either clopidogrel or ticlopidine, was approved for use in the EU for patients with a recent acute coronary syndrome (ACS). The approval of rivaroxaban in ACS was primarily based on findings of the phase III ATLAS ACS 2-TIMI 51 trial, which showed that after a median of 13.1 months of treatment with rivaroxaban 2.5 mg twice daily (combined with aspirin or aspirin plus either clopidogrel or ticlopidine) there was a statistically significant reduction in the rate of the primary composite endpoint, which was death from cardiovascular causes, myocardial infarction or stroke, compared with placebo. Rivaroxaban 2.5 mg twice daily was also associated with a reduction in all-cause and cardiovascular mortality. There was an increase in the risk of major bleeding and intracranial haemorrhage with rivaroxaban 2.5 mg twice daily compared with placebo; however, there was no increase in the risk of fatal bleeding. Aspirin plus either ticagrelor or prasugrel was not evaluated as background dual antiplatelet therapy in ATLAS ACS 2-TIMI 51 and the safety implications of rivaroxaban used in combination with such therapy are unknown. In conclusion, results of the ATLAS ACS 2-TIMI 51 trial suggest a potentially important role for rivaroxaban 2.5 mg twice daily co-administered with aspirin alone or aspirin plus either clopidogrel or ticlopidine in patients with a recent ACS.

Rivaroxaban: a review of its use in the treatment of deep vein thrombosis or pulmonary embolism and the prevention of recurrent venous thromboembolism

Rivaroxaban (Xarelto(®)), an oral direct factor Xa inhibitor, is approved for the initial treatment of deep vein thrombosis (DVT) and pulmonary embolism (PE), as well as the prevention of recurrent DVT and PE. It is administered at a fixed oral dose and does not require routine coagulation monitoring. In the EINSTEIN-DVT and EINSTEIN-PE trials, in over 8,000 patients with DVT and/or PE, a single-drug approach with rivaroxaban was shown to be noninferior to standard therapy consisting of subcutaneous enoxaparin sodium overlapping with and followed by an oral dose-adjusted vitamin K antagonist (enoxaparin-VKA) with regard to the incidence of symptomatic recurrent venous thromboembolism (VTE) after 3, 6 or 12 months of treatment. Rivaroxaban was generally well tolerated in patients with DVT or PE, with no significant between-group differences in clinically relevant bleeding between the rivaroxaban and enoxaparin-VKA groups. Notably, rivaroxaban was associated with a significantly lower rate of major bleeding compared with enoxaparin-VKA when EINSTEIN-DVT and EINSTEIN-PE data were pooled. Pharmacoeconomic analyses indicated that rivaroxaban may be a cost-effective alternative to enoxaparin-VKA for the treatment of DVT or PE and prevention of recurrent VTE. Extended prophylaxis with rivaroxaban reduced the incidence of symptomatic recurrent VTE to a greater extent than placebo in the EINSTEIN-Extension trial, but was associated with a non-significant increase in the risk of clinically relevant bleeding compared with placebo. In conclusion, rivaroxaban is a reasonable alternative to standard therapy for the treatment of DVT and PE, and as extended thromboprophylaxis.

Rivaroxaban: a review of its use in the prevention of stroke and systemic embolism in patients with atrial fibrillation

Rivaroxaban (Xarelto(®)), a direct factor Xa inhibitor, is approved for the prevention of stroke and systemic embolism in patients with atrial fibrillation (AF) in Canada or those with nonvalvular AF (NVAF) in the EU, US and Japan. It is administered at a fixed oral dose and generally does not require routine monitoring of coagulation parameters. In the ROCKET AF trial in patients with NVAF and a moderate to high risk of stroke, oral rivaroxaban 20 mg once daily (15 mg once daily in patients with moderate renal impairment) was noninferior to oral dose-adjusted warfarin once daily in preventing primary endpoint events (i.e. stroke and systemic embolism) in the per-protocol population (primary noninferiority analysis) and superior in the on-treatment safety population (primary superiority analysis). Several ROCKET AF subgroup analyses indicated that the treatment effect of rivaroxaban was consistent across patient subgroups stratified according to baseline factors, including the presence or absence of previous stroke or transient ischaemic attack. Patients with moderate renal impairment receiving the reduced rivaroxaban dosage (15 mg once daily) showed a treatment effect consistent with that seen with rivaroxaban 20 mg once daily in patients with normal renal function. The tolerability profile of rivaroxaban was generally acceptable in ROCKET AF, with no significant difference between rivaroxaban and warfarin in the incidence of major or nonmajor clinically-relevant bleeding events (primary safety endpoint). In the Japanese ROCKET AF trial, rivaroxaban 15 mg once daily (10 mg once daily in patients with moderate renal impairment) was noninferior to oral dose-adjusted warfarin once daily in the incidence of major or nonmajor clinically-relevant bleeding (primary study outcome). Thus, rivaroxaban is a reasonable alternative to warfarin for the prevention of stroke and systemic embolism in patients with NVAF.

Prevention of venous thromboembolism with new oral anticoagulants versus standard pharmacological treatment in acute medically ill patients: a systematic review and meta-analysis

INTRODUCTION

Venous thromboembolism (VTE) is a common and potentially avoidable cause of morbidity and mortality in patients hospitalized for acute medical illness.

OBJECTIVE

Our objective was to conduct a systematic review of studies that assessed the efficacy and safety of new oral anticoagulant (OAC) drugs versus standard pharmacological drugs and/or placebo in prevention of VTE in acute medically ill patients.

METHODS

PubMed.org and ClinicalTrials.gov databases were searched to identify studies that evaluated the efficacy and safety of a new OAC versus the standard pharmacological treatment and/or placebo in the prevention of VTE in medically ill patients. Relative risks (RR), weighted means and 95% CIs were calculated. Statistical heterogeneity was evaluated using Chi2 and I2 statistics. Two studies were included in the meta-analysis. The primary outcome in both studies was the composite of VTE-related death, symptomatic non-fatal pulmonary embolism (PE), symptomatic deep venous thrombosis (DVT) and asymptomatic proximal DVT. Both studies compared a factor (F)Xa inhibitor with enoxaparin in standard short-term thromboprophylaxis followed by a period where the FXa inhibitor was compared with placebo as prolonged thromboprophylaxis in medically ill patients. The primary major safety outcome in both studies was a composite of treatment-related major bleeding and clinically relevant non-major bleeding. A total of 14 629 patients were randomized.

RESULTS

Compared with subjects treated with enoxaparin followed by placebo, the RR of the primary outcome during the prolonged treatment period was 0.79 (95% CI 0.66, 0.94), the RR for the primary outcome during the first short-term treatment period was 1.03 (95% CI 0.81, 1.31). For major bleeding during the prolonged treatment period, the RR was 2.69 (95% CI 1.65, 4.39) for patients treated with an FXa inhibitor compared with enoxaparin/placebo. For major bleeding during the shorter treatment period, the RR was 2.01 (95% CI 1.10, 3.65) in favour of enoxaparin.

CONCLUSION

In acute medically ill patients, prolonged thromboprophylaxis with an oral FXa inhibitor is more protective than regular short-term treatment with enoxaparin. However, treatment with FXa inhibitors is significantly associated with major bleeding, both in long- and short-term treatment compared with enoxaparin.

Dabigatran etexilate: a review of its use for the prevention of venous thromboembolism after total hip or knee replacement surgery

Dabigatran etexilate (Pradaxa®, Pradax™, Prazaxa®) is indicated for the primary prevention of venous thromboembolic (VTE) events in adults who have undergone elective total hip replacement (THR) or total knee replacement (TKR) surgery. This article reviews the clinical efficacy and tolerability of oral dabigatran etexilate in patients undergoing major orthopaedic surgery, as well as summarizing its pharmacological properties and results of a cost-utility analysis. The discussion of clinical trial data focuses on comparative trials with the EU approved dosage regimen of once-daily subcutaneous enoxaparin sodium 40 mg. Dabigatran etexilate is an oral prodrug of the potent, rapidly acting, reversible, competitive inhibitor of thrombin, dabigatran. Dabigatran has predictable and consistent anticoagulant effects and does not require routine coagulation monitoring or dose titration. In the large, randomized, double-blind, phase III, noninferiority trials, RE-MODEL, RE-NOVATE and RE-NOVATE II, oral dabigatran etexilate, at dosages of 150 and 220 mg once daily, initiated postoperatively was shown to be noninferior to subcutaneous enoxaparin sodium 40 mg once daily (initiated prior to surgery) with regard to the incidence of the composite of total VTE events and all-cause mortality in patients undergoing TKR or THR surgery. In general, oral dabigatran etexilate was well tolerated in clinical trials of patients undergoing major orthopaedic surgery. There were no significant between-group differences in bleeding complications, including major bleeding, clinically relevant non-major bleeding or minor bleeding between the dabigatran etexilate or enoxaparin sodium groups. In addition, a cost-utility analysis from the perspective of the UK National Health Service indicated that dabigatran etexilate 220 mg once daily is dominant (i.e. more effective and less costly) to enoxaparin sodium 40 mg once daily in patients undergoing THR or TKR. Additional head-to-head comparisons would be beneficial to more definitively position dabigatran etexilate relative to other available oral treatment options for VTE prophylaxis, such as rivaroxaban and apixaban. In the meantime, dabigatran etexilate offers a convenient, effective and generally well tolerated treatment option for the prophylaxis of VTE in patients undergoing TKR and THR surgery.

Current management of massive hemorrhage in trauma

Hemorrhage remains a major cause of potentially preventable deaths. Trauma and massive transfusion are associated with coagulopathy secondary to tissue injury, hypoperfusion, dilution, and consumption of clotting factors and platelets. Concepts of damage control surgery have evolved prioritizing early control of the cause of bleeding by non-definitive means, while hemostatic control resuscitation seeks early control of coagulopathy.Hemostatic resuscitation provides transfusions with plasma and platelets in addition to red blood cells in an immediate and sustained manner as part of the transfusion protocol for massively bleeding patients. Although early and effective reversal of coagulopathy is documented, the most effective means of preventing coagulopathy of massive transfusion remains debated and randomized controlled studies are lacking. Viscoelastical whole blood assays, like TEG and ROTEM however appear advantageous for identifying coagulopathy in patients with severe hemorrhage as opposed the conventional coagulation assays.In our view, patients with uncontrolled bleeding, regardless of it's cause, should be treated with hemostatic control resuscitation involving early administration of plasma and platelets and earliest possible goal-directed, based on the results of TEG/ROTEM analysis. The aim of the goal-directed therapy should be to maintain a normal hemostatic competence until surgical hemostasis is achieved, as this appears to be associated with reduced mortality.

Coagulopathy and hemostatic monitoring in cardiac surgery: an update

OBJECTIVES

Cardiac surgery with cardiopulmonary bypass (CPB) causes severe derangements in the hemostatic system, which in turn puts the patient at risks of microvascular bleeding. Excessive transfusion and surgical re-exploration after cardiac surgery are potentially associated with a number of adverse outcomes including increased mortality.

DESIGN

This review describes coagulopathies occurring in cardiac surgery and the monitoring of these. Viscoelastic hemostatic assays (VHA) have routinely been used in cardiac surgery for more than 25 years and at least 16 studies (involving more than 3250 patients, including three randomized controlled trials) have compared VHA to routine coagulation tests (RCoT) with regards to their ability to predict bleeding and re-do surgery and also with regards to transfusion requirements secondary to hemostatic therapy based on VHA vs. RCoT.

RESULTS

All 16 studies demonstrated superiority with VHA as compared to RCoT both in predicting bleeding and need for re-do surgery and in reducing the total amount of blood transfusions by employing goal-directed administration of blood products based on VHA as compared RCoT based therapy or at the clinicians discretion.

CONCLUSIONS

The different types of coagulopathies observed in patients undergoing cardiac surgery requires adequate and timely hemostatic therapy and real-time monitoring with WHA such as TEG/ROTEM and whole blood platelet aggregometry.